Good afternoon (o;
I am doing some simulation of user interfaces where a spot light with a bitmap cast an image onto a semitransparent glass object...
Suddenly I discovered when I used color gradients in the bitmap that the gamma is totally wrong in rendering...looks like brightness over saturation...
Original bitmap:
and rendered output (bitmap is turned 180 degrees):
Also it depends from which side the camera is looking onto....
Weird gamma using spot light with bitmap
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Please upload a testscene that allows developers to reproduce the problem, and attach some images.
Please upload a testscene that allows developers to reproduce the problem, and attach some images.
Weird gamma using spot light with bitmap
Last edited by davorin on Thu Oct 18, 2018 1:27 pm, edited 1 time in total.
macOS 10.3.6, i7-7700, 32GB RAM, GTX1060 6GB
Re: Weird gamm using spot light with bitmap
Have you specified the correct gamma value for the image?
How do your color management settings look like, are you using filmic?
Can you upload a testscene with all textures that shows the problem?
How do your color management settings look like, are you using filmic?
Can you upload a testscene with all textures that shows the problem?
Re: Weird gamm using spot light with bitmap
Tried a little with gamma settings...but higher values gets me more of the left side being dark...
color settings I didn't touch as other stuff looks normal to me...
Attached the scene...think it should contain all bitmaps..
BTW: What is best for a spot light bitmap?
Using a black background or using a transparent background?
color settings I didn't touch as other stuff looks normal to me...
Attached the scene...think it should contain all bitmaps..
BTW: What is best for a spot light bitmap?
Using a black background or using a transparent background?
- Attachments
-
- test_scene.zip
- (1.44 MiB) Downloaded 152 times
macOS 10.3.6, i7-7700, 32GB RAM, GTX1060 6GB
Re: Weird gamma using spot light with bitmap
This is now with a higher gamma value for the bitmap (5):
Note the fine line at the left which should be not lit...
Especially the effect can be seen with this bitmap I used originally.
The gradients around the white circles are almost flat:
Note the fine line at the left which should be not lit...
Especially the effect can be seen with this bitmap I used originally.
The gradients around the white circles are almost flat:
macOS 10.3.6, i7-7700, 32GB RAM, GTX1060 6GB
Re: Weird gamma using spot light with bitmap
You are using filmic color management.
Your image is probably completely over-exposed. Filmic has this behaviour that overexposed colors get desaturated instead of blowing out.
Also, the gamma of your image is probably 2.2, not 5, which leads to excessive banding because the 8 bit image does not have enough information.
Attached is a fixed scene where these problems are solved.
Your image is probably completely over-exposed. Filmic has this behaviour that overexposed colors get desaturated instead of blowing out.
Also, the gamma of your image is probably 2.2, not 5, which leads to excessive banding because the 8 bit image does not have enough information.
Attached is a fixed scene where these problems are solved.
- Attachments
-
- test_scene.zip
- (1.44 MiB) Downloaded 134 times
Re: Weird gamma using spot light with bitmap
Wow..that looks great...think I have to adjust the other lamps as the cube below is now too dark (o;
many thanks
richard
many thanks
richard
macOS 10.3.6, i7-7700, 32GB RAM, GTX1060 6GB
Re: Weird gamma using spot light with bitmap
Or you have to make the overall image brighter by adjusting the tonemapper scale, but in turn make the spot light darker.
By the way, I disabled automatic tonemapping, this is usally better once you know the tonemapping scale your scene needs.
And one general tip: if you use filmic, sometimes switch to default to make sure your image is not completely over-exposed.
By the way, I disabled automatic tonemapping, this is usally better once you know the tonemapping scale your scene needs.
And one general tip: if you use filmic, sometimes switch to default to make sure your image is not completely over-exposed.